MusicReasonRooms, Monitoring, and Acoustic Calculations
How much quieter is it at that distance?
Enter a reference and a target distance from a sound source. This tool estimates the free-field level change between them, assuming an idealized point source with no room reflections, directivity, or air absorption.
Answer
Want to learn more? Room Modes and Low-Frequency Behavior
Understand
This is the idealized inverse-square-law drop-off for a point source radiating equally in all directions with nothing else in the space. Real rooms add reflections that partially offset this drop-off, and real sources are rarely perfectly omnidirectional, so a measured result in an actual room will typically depart from this free-field estimate.
Worked example
Doubling the distance from a source, from 1 meter to 2 meters, drops the level by about 6.02 dB in free-field conditions. Measuring at the same distance twice naturally shows zero change.
Method and limitations
Level difference is 20 × log10(referenceDistance / targetDistance). This tool does not model room reflections, source directivity, air absorption at high frequencies, or any hearing-safety threshold; it is a simple geometric estimate only.
Where the free-field assumption breaks down
Indoors, reflected sound from walls, ceiling, and floor adds back some of the energy this inverse-square estimate predicts you would lose, which is why a real room's measured drop-off with distance is almost always gentler than this calculation suggests. The free-field assumption holds best outdoors or in a well-treated anechoic-style space; a typical room departs from it more the closer you are to reflective surfaces.